Ember 数据无法读取未定义的属性“async”

将 Ember v1.8 beta 3+ 与 Ember Data 1.0 beta 10 一起使用 - 您会收到以下错误：

Error while processing route: index Cannot read property 'async' of undefined TypeError: Cannot read property 'async' of undefined
    at Relationship [as _super$constructor] (http://builds.emberjs.com/canary/ember-data.js:9523:46)
    at new BelongsToRelationship (http://builds.emberjs.com/canary/ember-data.js:9736:12)
    at createRelationshipFor (http://builds.emberjs.com/canary/ember-data.js:9840:16)
    at http://builds.emberjs.com/canary/ember-data.js:6366:41
    at http://builds.emberjs.com/canary/ember-data.js:9307:20
    at cb (http://builds.emberjs.com/ember-latest.js:15907:13)
    at OrderedSet.forEach (http://builds.emberjs.com/ember-latest.js:15703:13)
    at Map.forEach (http://builds.emberjs.com/ember-latest.js:15911:19)
    at Function.Model.reopenClass.eachRelationship (http://builds.emberjs.com/canary/ember-data.js:9306:42)
    at Ember.Object.extend._setup (http://builds.emberjs.com/canary/ember-data.js:6365:26) 

尽管您的模型设置正确：

App.Color = DS.Model.extend({
  color: DS.attr(),
  foo: DS.belongsTo('foo', {async:true})
});


App.Foo = DS.Model.extend({
  foo: DS.attr()
});

例子：http://emberjs.jsbin.com/OxIDiVU/1111/edit http://emberjs.jsbin.com/OxIDiVU/1111/edit

这是 Ember/Ember-data 版本的错误。 Ember 在 Ember 1.8 beta 3 中更改了其 Map 实现，破坏了任何低于 1.0 beta 10 的 Ember Data 版本。

这是github问题：https://github.com/emberjs/data/issues/2323 https://github.com/emberjs/data/issues/2323

它已在 1.0.0-beta.11+canary.2997e47034 或更高版本中修复。